γ-C2S is known as a kind of substance that it does not react with water at room temperature. However it could react with the CO2 producing CaCO3 and silica gel as the carbonation products. Thus γ-C2S can be used as a mineral addition to improve the compressive strength and durability of concrete. On the other hand, the manufacture of γ-C2S can give an effective utilization of industrial by-product with low energy consumption and low CO2 emission. This paper aims to summarize the development situation on this field.